There is an ever increasing demand for power conversion and regulation circuitry to operate with increased efficiency and reduced power to accommodate the continuous reduction in size of electronic portable devices. Many times these devices are battery powered, and it is desirable to utilize as little power as possible to operate these devices so that the battery life is extended. Voltage regulators have been implemented as an efficient mechanism for providing a regulated output in power supplies. One such type of regulator is known as a switching regulator or switching power supply, which controls the flow of power to a load through pulse-width modulation (PWM), such as can occur by controlling the on and off duty-cycle of one or more switches coupled to the load. Many different classes of switching regulators exist today.
One type of switching regulator is known as a synchronous switching regulator. In a synchronous switching regulator, an inductor is used to maintain current flow that is switched from two separate sources. The two sources can include a high-side switch, such as a high-side field-effect transistor (FET), and a low-side switch, such as a low-side FET and a freewheeling diode. Once the high-side FET is turned off, magnetic power stored in the inductor dissipates to force current through the inductor by changing the voltage of the inductor source node to negative relative to ground. The freewheeling diode thus conducts current from ground to the inductor after the high-side has been turned off and before the low-side FET has been turned on. In this way, current continuously flows through the inductor in the times between activation of the high-side and the low-side switches.
In a synchronous switching regulator, the activation of the high-side switch and the low-side switch is kept mutually exclusive to avoid shoot-through, which is a short circuit of a positive supply voltage to a negative supply voltage (e.g., ground) that can occur through simultaneous activation of both the high-side switch and the low-side switch. As such, a time delay known as a deadband time can be introduced into the PWM control, such that a rising-edge and/or a falling-edge can be delayed to prevent simultaneous activation of the high-side and the low-side switches. Typically, the amount of deadband time delay can be based on a system clock. However, such deadband time delays are typically configured for a conservative amount of time because a system clock may not be able to provide sufficient resolution for optimum switching efficiency.